* listbox.t: don't call resetGridInfo for most window managers

  Calling resetGridInfo seems to be responsible for most (all?) test
  failures in listbox.t.

  Experiments show that these lines would even cause failures with
  current Tcl/Tk.

  So now it's only activated for mwm - according to the comment only
  mwm (and some other WMs) need this.
* errordialog.t: make sure main window is destroyed if some tests fail

  Timeout is currently 20 seconds. If the main window is still active
  then it is destroyed.
POD fix Tk::Text

in INDICES, outdent between base & modifiers
POD fix Tk::Text [2]

in INDICES, outdent before modifiers summary